Angelfish With Something On Her Head

[SiangHweeOh]

Hi,I'm new around here not sure how to make a post(sorry) My angelfish suddenly has something on her head a few hours after one of my guppy's death. Does this problem have something to do with the hole-in-the-head disease? If so, how can I cure it please help!

 

[Chad]

There are several things that it could be. A photo would really help if you can.